Microstructural investigation of nanocellulose addition on the performance of cementitious materials cured in aggressive environments

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Abstract

During the last years, incorporation of nano-constituents into cement-based construction materials has been increasingly spreading thanks to their unique physicochemical properties which enable both nano- and micro-mechanical improvement of cementitious composites. It has been well established that besides increasing concretes strength, refinement of pore size occurs causing a significant reduction in total porosity values and improvement in specimens durability. The present work aims at the analysis and performance evaluation of nanocellulose (NC) enriched Ultra High Durable Concretes (UHDC) exposed to aggressive environmental conditions (i.e. chemical attack - XA environmental exposure class). To this purpose, two reference UHDC materials containing crystalline admixtures and steel fibers were compared with mixes holding also cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) into their structures. In all cases, NC loading remained constant and equal to 0.15% (by %wt of cement amount).The excellent reinforcing capabilities of NCs are demonstrated by the enhanced fracture resistance properties of the cementitious matrix. Additionally, microstructural analysis results of as derived specimens suggest that the use of NCs can lead to the development of materials with advanced textural and morphological characteristics and therefore widen their application prospects to aggressive environmental conditions.